1. Field of the Invention
The instant invention is related to the art of connectors, and more particularly to a positioning mechanism adapted to hold an integrated circuit (IC) package, e.g. a land grid array (LGA) package, on a socket mounted on an electrical substrate, such as a printed circuit board (PCB).
2. Description of the Prior Art
With the development of electrical components on an electrical substrate, e.g. a PCB, toward miniaturization, multifunction and high integration, it becomes more and more concerned to secure position relationships between the electrical components, and to decrease real estate that each component occupies on the PCB as possible as specific conditions permit.
LGA sockets of old style have the problems mentioned above. Referring to FIGS. 9 and 10, a conventional LGA socket assembly 90 is shown, and comprises a dielectric housing 92 with a plurality of terminals 920 planted thereon, a metal stiffener 94 harnessed on the housing 92, an metal urging member 96 and a metal pressing member 98 attached to opposite sides of the metal stiffener 94. The urging member 96 has a shaft 960 rotatably secured on the metal stiffener 94 and a handle 962 extending perpendicularly from one distal end of the shaft 960.
In mounting the LGA socket assembly 90 on one side of a PCB in a re-flow procedure (not shown), solder balls provided to electrically bridge corresponding terminals and corresponding circuits on the PCB are melted and then cooled, thereby attaching the LGA socket assembly 90 on the PCB.
With this configuration of the LGA socket assembly 90, two main problems of the LGA socket assembly 90 stand out. First one, the stiffener 94, the urging member 96 and the pressing member 98 are made of metal. This results in a relatively heavy weight of the LGA socket assembly 90. Consequently, the LGA socket assembly 90 is prone to slant or fall off during a second re-flow procedure in which the PCB is reversed to facilitate soldering other components on the other side of the PCB.
Second one, in use, the handle 962 and the pressing member 98 are rotatable around the opposite sides of the stiffener in a space, respectively. The space is much higher than a total height of the LGA, even a total height of a top surface 930 of an IC package 93 with respect to the PCB. Differently put, relatively higher space needs to be provided above the LGA for rotating of the handle 962 and the pressing member 98. This is prone to bring un-convenience in assembling, disassembling or operating other components.
Accordingly, a new positioning mechanism, which overcomes the disadvantages pointed out above, is desired.